Difficulties are often encountered in the implantation into bone of various prostheses, such as dental implants. Techniques currently employed can contribute to slow healing and less than optimal integration of the implant, and may in some cases lead to excessive bone fracture. Such difficulties are particularly common and/or acute when the site is at a narrow, atrophic bone ridge.
Various dental wedges and like devices are known in the art, as evidenced by the disclosures of the following United States patents:
No. 1,598,458 No. 5,743,738
No. 2,465,305 No. 6,030,390
No. 4,631,030 No. 6,079,978
No. 4,696,646 No. 6,146,138
No. 4,881,534 Des. 439,667
No. 5,217,371
These patents do not however adequately address difficulties and deficiencies that are inherent in conventional implantation practices presently employed.
The broad objects of the present invention are to provide a novel bone spreader, and a novel method for implant insertion, by which the difficulties and deficiencies described above are avoided, or at least ameliorated, and by which advantages hereinafter set forth are realized.
It has now been found that certain of the foregoing and related objects of the invention are attained by the provision of an instrument having a forward end portion constructed for bone penetration and terminating at a tip, and a rearward end portion constructed for receiving driving force. The instrument is comprised of a relatively wide and thin blade component, which has a relatively sharp peripheral edge portion that extends effectively about at least its forward end portion and that includes laterally spaced edge sections, and an integral ridge component. The ridge component extends rearwardly from adjacent the tip, on one surface of the blade component, and a leading end element thereof, disposed at or closely adjacent the tip, is formed to facilitate bone penetration.
In more specific forms of the instrument, at least a forward end portion of the ridge component will desirably be of substantially curvilinear cross section, and more particularly of half-round form. The forward end portion of the ridge component will usually be tapered, in its lateral and/or its transverse dimensions, so as to provide the penetrating leading end element. The rearward end portion of the instrument will conveniently be provided at least in part by the ridge component, which will normally be substantially rectilinear and disposed intermediate the lateral edge sections of the blade component; generally, the blade component will be laterally symmetric about a central axis on which the ridge component is disposed. One surface of the blade component will beneficially have a generally convex contour, taken in planes transverse to the ridge component along at least a portion of the length of the instrument, and most preferably the blade component will be of generally plano-convex cross section. The blade component will advantageously be gently pointed or will be formed with a rectilinear edge section at the tip of the instrument, and usually the instrument will be integrally formed from a single piece of stainless steel.
Other objects of the invention are attained by the provision of a method for implant insertion, comprising the steps: (a) identifying an implantation site on the surface of a bone member; (b) driving the described bone-spreading instrument so as to spread bone tissue and thereby form an inwardly-extending recess at the implantation site, the recess being dimensioned and configured for the ready receipt of an implant element; (c) removing the instrument from the recess; and (d) inserting the implant element. Normally, the construction of the instrument will be such that a groove of generally semicircular cross section is formed to extend inwardly along one side of the recess, to optimally accommodate a conventional dental implant having a cylindrical root element, with the recess preferably comprising an inwardly tapered plane portion, of relatively wide, thin cross section, and a relatively narrow groove portion extending longitudinally along one side of the plane portion. Depending upon the hardness of the bone at the implantation site, the method may include a preliminary step of forming a pilot slot for receiving the spreader instrument.